There are several ways to do this. You can round 9 to 10, since it is fairly close; dividing by 10 is easy, and rounding 9 to 10 gives you an error of about 11%.
Also, you can round the first two digits of 524 to the closest multiple of 9; in that case, it is easy to divide it by 9.
In any case, it should be possible to do all these calculations mentally (that's the main point of estimating).
58.2222
524
58.2222
131
524
524
Yes. 524 divided by 4 is 131.
0.0859
2
81.6667
79.4444
53